Finalizer task switch bug

[Moelf]

running finalizer: ErrorException("task switch not allowed from inside gc finalizer")
ijl_error at /cache/build/default-amdci4-6/julialang/julia-release-1-dot-9/src/rtutils.c:41
ijl_switch at /cache/build/default-amdci4-6/julialang/julia-release-1-dot-9/src/task.c:634
try_yieldto at ./task.jl:910
wait at ./task.jl:984
#wait#621 at ./condition.jl:130
wait at ./condition.jl:125 [inlined]
wait_close at ./stream.jl:488
close at ./stream.jl:509
unknown function (ip: 0x7f3a580d85c2)
_jl_invoke at /cache/build/default-amdci4-6/julialang/julia-release-1-dot-9/src/gf.c:2758 [inlined]
ijl_apply_generic at /cache/build/default-amdci4-6/julialang/julia-release-1-dot-9/src/gf.c:2940
manage at /home/jiling/.julia/packages/ClusterManagers/MMYmO/src/condor.jl:94